The 34-year-old was named in Ashton's preliminary 47-man England training party on Friday and now intends to win a place in the final 30 for the tournament.
The veteran number eight, who has won 77 caps, last featured for England as replacement in the 2006 Six Nations but excelled in Wasps' Heineken Cup victory this year.
Dallaglio told The Sun: "I'm under no illusions, I have a lot to do to make the 30, but the same applies to every one of us.
"But, just as I admitted I was not playing well enough for consideration before the RBS 6 Nations, I believe I've made big strides back towards top form during the second half of our domestic season.
"Those of us selected have been handed the opportunity to fight for a tilt at the 2007 World Cup.
"Not one will give less than all he has to give."